I am not really asking a question on these speakers, since I may have had the only pair in the whole country. I just want to make a few comments on these fantastic little speakers.

I purchased these speakers by chance, I heard about them and drooled over them in the late 80's, but I could not afford any high end gear at that time.

After spending hours searching up and down on the internet, I couldn't find diddly-squat on these speakers, but there are no shortage of info for the Sonographe SA-120 and the SP-1, even the SG-3 is mentioned quite a bit on the net, that really makes me sick.

Anyway, the SL-21 has very attractive real oak veneer, the front and back are sloped, hence involved some time-align design, but like I said, I could not find anything on them. Even when I called C-J, the guy named Ed who handled vintage C-J equipment couldn't tell me a whole lot about them, at least Sota could tell me quite a bit about the SG-3 for crying out loud.

The SL-21 has very wide soundstage and solid bass for it's size, 6.5" woofer and 1" soft dome tweeter, and a 1" port in the front baffle, they also have very nice midrange. The speakers virtally disappear from the room while playing, that proves these speaker are well designed. During the knuckle test, I heard no cabinet echo or resonance, very solidly built, that tells me they are well damped inside.

If anyone who know about them, please charm in. These may be the only pair that left in the country, and they are not for sale.

all cj speakers (synthesis and later sonographe) were well kept secrets) As as the case with motiff and other cj branded experiments, they ere ambitious, among the best values in audio, and for a variety of reasons, abandoned....go figure.

You may have one of two pairs in the US and I'm sure there are others. I bought mine from a dealer in Tucson many years ago. The dealer quit bringing them in because everytime someone heard them compared to his big expensive speakers they ended up buying the CJ's. a great little speaker.

I have never heard of the synthesis speaker by CJ, but as far as CJ's keeping their speakers a secret that's very interesting.

I would very much like to learn more about the technical aspect of the SL-21, like who were the designers, were the folks at Sonographe, or the folks at CJ? What components did they use, and the crossover design?

My SL-21s front grills are long gone, however, my 1988 Audio magazine advertisment with the picture of the SL-21 didn't show any front grill, the Audio Annual Buyers Guide said the SL-21 grills were optional.

Can anyone tell me if your SL-21 came with front grills? If so, what do they look like, and are they easy to make?

I believe that the speakers used the very unusual Bessell filter alignment which features both a very rapid out of band rolloff and is maximally phase coherent as well as being fairly flat in band. The Spica speakers are another example of a loudspeaker that uses this crossover alignment.

the gentleman(can't remember the name) that designed cj's speakers left and started his own line, which failed too. they all ere outstanding. sota's panorama line were incredible as well. two unit sats and subs thats outwattpuppied the watt-puppy...once again they didn't last.

I believe Dave Fokos designed speakers for C-J . I do not know if he designed SL-21.I own other speaker of his design Icon Acoustics model Parsec. They sound great. Icon Acoustics was his own company. After IA went out of business Fokos worked for Boston Acoustics and Bay Audio. Do a search for Dave or David Fokos.Quote from inc.com :

In June 1984 (Dave )Fokos, fresh out of college, landed a job as a loudspeaker designer for Conrad-Johnson, a high-end audio-equipment maker in Fairfax, Va. In the next four years Fokos would be the principal designer of 13 speaker models for C-J, an experience he calls "an invaluable apprenticeship" for running his own show. Fokos founded Icon Acoustics in April 1989, believing the niche he sought had scarcely been explored.

I have had a pair of the SL-21s since the mid 80's and people who come to visit are still astounded by the sound quality. They're paired with Yamaha separates from the same era (C20 pre-am and M20 amplifier). Unfortunately the grills have both "disintigrated" and, when I called Conrad Johnson I was told they could not find any in the warehouse. Doesn't matter..the speakers look great without the grills. I remember the first time I heard them. I was in an upscale stereo store in Cleveland (no longer in business) and I heard all of this great sound and I couldn't quite locate the source. It turns out all that sound was coming from two little boxes sitting on the floor of the store. They have wonderful musicality and a great sound stage...even better than my B&W's which are much newer.

I recently aquired a pair speakers that sound similar to these. A metal tag on back states manufactured by Conrad Johnson of Fairfax, Virginia Model Number LM20 Serial Number 0200268. The other speaker's tag is missing. They sound good. The cabinets are clean without moajor blemish. They are heavy and well constructed. The foam grill covers are good but not perfect. I am in Atlanta. I would like to know more about them if anyone can shed some light.

Sonographe seems to have been c-j's 'budget' line. The models were similar to Synthesis, but were less expensive and had less impressive cabinets. Synthesis speakers were designed by Dave Fokos, who later founded his own mail order company, Icon Acoustics, worked as a designer for another company or two, and went into photography. A local store in Charlottesville Va handled all the c-j stuff and I got to listen to several models of Synthesis speaker: the 2-way LM-210, LM-260, LM-260i, and 3-way LM-300. I also heard the Sonographes. I believe the Synthesis speakers used Bessel filter crossovers, which Jon Bau had popularized with the Spica TC 50. The imaging was outstanding on all of them, though the bass of the 210 was a bit underdamped, while the 260 was overdamped, but to very nice effect. Deep organ notes produced silence but tympani sounded wonderful - you could hear the decay clearly separate from the sound of the mallet striking the head. The 260i extended the bass. Lewis Lipnick was quoted as liking Synthesis speakers in a NYT article, though of course he went on to praise other brands. I couldn't afford the speakers at the time, but I'd love to have a used pair of 260s or even 210s. The 260s had uncanny imaging if not a lot of depth. The 210s had more depth if not quite as much specificity, and had a really ballsy midrange with solid state, but with cj tubes they sounded extremely liquid and sweet. Great dynamics made them great for either rock or classical. A pair of CM-205s sold just recently on Audiogon. These are similar to the 210s only standmounts with less low end than the 210, which is a tower, like the 260 and above. The seller said they use the same drivers as the 210, in which case they should be pretty capable speakers. All the Synthesis designs got excellent reviews in Sphile. Now I know that nearly everything else does too, but the reviews were good enough that taken together with cj's reputation they should have been able to move some wood. I don't know why these speakers are not more common. They are scarce as hen's teeth. I get the feeling that c-j didn't place the line in a lot of stores. I can't imagine customers were disappointed with them. Also, Synthesis made too many different models given the volume of business. They had silly variations: for example the 300 was just a 310 in a clunky cabinet. I think there was a 200 that was a 210 in a clunky cabinet. Very bad marketing. Dave Fokos is still around and from time to time the idea occurs to me of asking if he has the specs for a DIY project. I would welcome any news or stories anyone has to share. I hope to pick up a pair of one of these models sooner or later, though locating a pair is not trivial.